Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Virtual duck bills demonstrate species coexistence

01.03.2007
Ecologists continue to debate how different species manage to coexist. If two species use identical resources, such as food, invariably one will be more efficient and out-compete the other.

The classical explanation is that each species has evolved morphological or physiological traits that allow it to exploit some resources more efficiently than all other species. Such partitioning of resources essentially provides each species with exclusive access to resources necessary for its survival.

Although coexistence is often attributed to interspecific differences in morphology, direct evidence is relatively rare. Dabbling ducks, which include the ubiquitous mallard, are a good example. Dabbling ducks are primarily filter-feeders.

They use lamellae, which are comb-like projections on the bill, to sieve food particles from pond water. Many ecologists, including Darwin, suggested that ducks coexist because interspecific differences in the spacing of bill lamellae allow each species to consume food particles of different sizes. Research published in the March issue of the American Naturalist by Brent Gurd of Simon Fraser University has demonstrated that interspecific differences in lamellar length, not spacing, allow ducks to partition food by size.

"Lamellar spacing alone does not lead to resource partitioning," said Gurd, "ducks with small spacing are more efficient than species with wide spacing because they retain a wider range of particle sizes than species with wide spacing. In order for variation in bill morphology to lead to resource partitioning, each trait must impose both costs and benefits on foraging ducks. It is the trade-off between these costs and benefits that allows resources to be partitioned."

"Foraging ducks are faced with the cost of separating food particles from detritus particles like sand and silt" said Gurd. "To do this, they alter the position of the upper and lower bill while they are feeding. This alters the size of the gap between the lamellae on the upper and lower bill, which allows them to determine the size of the particles they filter and ingest. By avoiding particle sizes that contain too much detritus, ducks increase their foraging efficiency."

However Gurd found that avoiding detritus reduces the rate at which ducks can filter water. "It is this trade-off between avoiding detritus and foraging rate that allows ducks to partition resources" said Gurd. "Ducks with long lamellae are more efficient at selecting smaller food particles while ducks with short lamellae, like mallards, are more efficient at selecting larger particles."

To test his idea, Gurd created virtual bills using computer software typically used by engineers to design complex machinery. "The software allowed me to create exact, three-dimensional replicas of duck bills complete with articulating joints" said Gurd. "The replicas allowed me to determine the particle sizes each duck could ingest and the rate at which they could ingest them."

D. Brent Gurd, "Predicting resource partitioning and community organization of filter-feeding dabbling ducks from functional morphology" American Naturalist 169:334-343 (2007)

Patricia Morse | EurekAlert!
Further information:
http://www.uchicago.edu

More articles from Ecology, The Environment and Conservation:

nachricht Safeguarding sustainability through forest certification mapping
27.06.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht Dune ecosystem modelling
26.06.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

CCNY physicists master unexplored electron property

26.07.2017 | Physics and Astronomy

Molecular microscopy illuminates molecular motor motion

26.07.2017 | Life Sciences

Large-Mouthed Fish Was Top Predator After Mass Extinction

26.07.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>